In vitro exposure to di-(2-ethylhexyl) phthalate (DEHP) stimulates spontaneous feline uterine contractions

Di-(2-ethylhexyl) phthalate (DEHP) is widely used as a plasticizer in various products such as PVC-derived plastics, toys, packaging materials, cosmetics, and pharmaceuticals. This study aimed to investigate the effect of DEHP on spontaneous contractions of the feline uterus in vitro. Tubal 1-cm uterine samples prepared from 10, 9, and 12 uteri obtained from adult cats in estrus (n = 5), diestrus (n = 5), and interestrus (n = 5), respectively, after ovariohysterectomy were suspended in an isolated organ bath in aerated Krebs solution at 39 +/- 1 degrees C, and an initial 1 g tension was given. After 1 h equilibration of tissues, the spontaneous contractions were recorded for 10 min as control. The effects of solvent and DEHP (0.001-100 mu M) on contractions were then evaluated in terms of frequency and mean amplitude parameters. It was observed that DEHP had no effect on uterine contractions of cats in interestrus. However, DEHP significantly increased the mean amplitude of uterine contractions during the estrus and diestrus periods at concentrations of 1 mu M and 10 mu M, respectively, depending on the dose (P < 0.05). Decreases in the frequency of the contractions in the estrus and diestrus periods were not statistically significant (P > 0.05). 'this study, carried out for the first time in cats, showed that DEHP has a stimulatory effect on uterine contractions. We concluded that disruption of the uterine contractions, which are essential for physiological reproductive processes such as regular estrous cycles, sperm and zygote transport, implantation and continuation of pregnancy, by DEHP exposure may cause many reproductive problems.